Force Chain Lifetimes in Shear Bands in Sands Conference Paper uri icon

abstract

  • We present imaging-based experimental data of the meso-scale kinematics associated with force chain buildup and collapse within shear bands in sands. Dense sand specimens are subjected to plane strain compression in an apparatus in which the zero-strain conditions are enforced by glass walls which permit imaging if in plane deformations. Grain-scale displacements are quantified continuously through the experimental technique of Digital Image Correlation (DIC). We evaluate the meso-scale kinematics within the shear bands, the patterns in which have been shown to be strongly indicative of force chain buildup and collapse. We follow the change in these kinematic patterns from global softening to critical state deformation, and discuss the implications of the observed microstructural changes with regard to the evolution in macroscopic response. The kinematics suggest the transition from softening to critical state to be defined microstructurally by a distinct collapse event of the force chains formed at shear band onset at peak stress. Critical state then is defined microstructurally by the continual buildup and collapse of force chains. Force chain spacing during softening appears periodic, the frequency of which may be related to associated vortex structures. © 2009 American Institute of Physics.

author list (cited authors)

  • Rechenmacher, A. L., Abedi, S., & Chupin, O.

publication date

  • January 1, 2009 11:11 AM

publisher

  • AIP  Publisher